Petrochemical products

The technology relates to comprehensive processing of pyrolysis tar (liquid residues from gasoline pyrolysis), produced in PKN „Orlen” S.A. in Płock, till now fully disposed of as a component of heavy heating oil C-3.

Using the pyrolysis tar produced in PKN „Orlen” S.A., there is a possibility to produce petrochemical naphthalene, used to manufacture phthalic anhydride and b-naphthol in quantity about 10 thousand TPY. Processing of pyrolysis tar, would also enable to produce scrubbing oil, in short supply on the domestic market, used in coke oven plants (about 20 thousand TPY) and highly aromatic oil to produce carbon black (about 35 thousand TPY). Total market value of the products mentioned is about Є 1520 mil.

A brief description of the technology

The technology comprises separation of pyrolysis tar by distillation under reduced pressure, using flash distillation and rectification. It allows to obtain suitable hydrocarbon fractions with boiling point in defined temperature ranges, which (except for naphthalene fraction) can be ready market products.

Obtaining pure naphthalene from pyrolysis tar involves distilling separation of the hydrocarbon fraction enriched in naphthalene, with boiling point usually between about 210 and 225 °C and containing > 70 wt. % naphthalene. This fraction is then subjected to the crystallization process and centrifugation or directly to fractional crystallization from the melt. This process allows to obtain naphthalene of 98–99.5 wt. % with high efficiency.

Advantages of the technology offered

Application of the technology of complex processing of pyrolysis tar would contribute to increase in the degree of crude oil processing and consequently to improvement in technical and economical indicators of the Olefin Plant in Polish Petroleum Concern „Orlen” S.A. in Płock.

The technology to process pyrolysis tar can be used in petrochemical refineries possessing a distillation installation equipped with columns for vacuum rectification and flash distillation. In order to produce pure naphthalene, there is necessary an equipment for crystallization with centrifugation or fractional crystallization.

References

The technology of complex processing of pyrolysis tar with this method has been investigated on the 1/4-technical scale. Obtained products: naphthalene, aromatic oil for manufacturing of active carbon black and methyl naphthalene fraction (scrubbing oil for coke oven plants) have been successfully tested, respectively, in: ZAK S.A., carbon black plant in Jas³o Refinery and Institute for Chemical Processing of Coal in Zabrze.